The invention concerns a transport device for conveying an object to be transported between an input point where the object to be transported can be inserted into and removed from the transport device, and a supply point where the object to be transported can be supplied to an RT tube of a cryostat, wherein the object to be transported comprises an NMR measuring sample and a sample holder, wherein the input point is both horizontally and also vertically spaced apart from the supply point, and wherein a transport tube is provided for pneumatically conveying the object to be transported within the transport tube from a first transfer point at the lower end of the transport tube to a second transfer point at the upper end of the transport tube.
A device of this type is disclosed in DE 3729819 C2 [1].
NMR spectrometers have been further developed and become much more powerful since the 1950s. They are practically always operated with a fast computer in order to especially enable the application of the fast Fourier Transformed NMR spectroscopy method (FFT-NMR), and they are moreover almost exclusively operated with superconducting magnet systems with fields of up to 20 Tesla.
The installed computer not only enables performance of fast FFT but can also be used for automation tasks such as e.g. automated transport of the NMR measuring sample from a location that is easily accessible to the user to the magnetic center of the superconducting magnet and back. This automated transport is very advantageous, in particular, for high-field magnets with fields between 16 T and 20 T, since these magnet systems may have a height of more than 2.50 meters and the NMR measuring sample must be introduced in the upper area of the magnet system.
The “SampleJet” [3] of the company Bruker is a conventional transport device. It is a sample automated device with a magazine capacity of up to 480 NMR sample tubes that can be manually supplied to the automated device magazine in the form of 5 cassettes of 96 pieces of sample tubes each together with up to 47 objects to be transported. The objects to be transported may be supplied to the NMR measurement either individually, in selected or sequential order. The sample automated device can combine NMR sample tubes (20) with sample holders (19) to form objects to be transported (18), and subsequently supply these to the NMR measurement or supply the objects to be transported (18) directly and without further manipulation to the NMR measurement.
A further conventional transport device is the “BACS” [4] of the company Bruker. It is a sample automated device with chain cycle, which is available with a magazine capacity of 60 or 120 objects to be transported. The objects to be transported can be supplied to the NMR measurement individually, in selected or sequential order.
One further conventional transport device is the “NMR Case” [5] of the company Bruker. It is a sample carousel automated device comprising a magazine capacity of 24 objects to be transported. The objects to be transported can be supplied to the NMR measurement individually and only in sequential order.
A further conventional transport device is the “Sample Changer” ASC [6] of the company Jeol. It is a sample carousel automated device that is available with magazine capacities of 8, 16, or 64 objects to be transported. The objects to be transported can be supplied to the NMR measurement individually, in selected or sequential order.
A further conventional transport device is the “Carousel Autosampler” [7] of the company Varian. It is a sample automated device comprising a magazine with a receiving capacity of 9 objects to be transported. The objects to be transported can be supplied to the NMR measurement individually, in selected or sequential order.
The above-described transport devices are disadvantageous in that the user must access the height range of the upper end of the RT tube in order to supply the automated device with objects to be transported (and in [3] to supply the cassettes or in [5] to change the carousel cassette), which necessitates auxiliary means such as ladders, stairs or even scaffoldings for larger magnets. Auxiliary means of this type, however, are awkward and some of them are very expensive.
[2] discloses an automatic transport device (“SampleRail” of the company Bruker), which is schematically shown in FIG. 2b. This conventional transport device conveys the object to be transported from a location that is easily accessible to the user (point B′) via points C′ and D′ to a supply point Z, from which the object to be transported can be inserted into the RT tube of a cryostat 1, and back. This transport device compensates for a height difference between the points B′ and C′ by means of a pneumatically driven linear axis 31. The linear axis 31 has a linear guidance with integrated pneumatic drive comprising a piston with mechanically connected carrier, to which the parts to be moved can be fixed, a cylinder and corresponding sealing elements. The object to be transported is thereby located in a transport container 32 that his decoupled from the carriage of the linearly arranged linear axis 31 at point C′, and is transferred through coupling to the carriage of a horizontally arranged linear axis. The carriage conveys the object to be transported to point D′. A flexible hose 33 is located between point D′ and the supply point Z to ensure guidance of the object to be transported 18 even when the vibration-damped and thereby “floatingly” disposed cryostat is lifted or inclined due to evaporation of the coolant.
The transport device of [2] is disadvantageous in that, for conveying the object to be transported in a horizontal and vertical direction, an expensive transport container 32 with expensive coupling adaptation is required for receiving the transport container on the horizontal and vertical linear axis. Since the transport container 32 is not confined to the linear axis 31 during the vertical movement, but is moved outside of and along the linear axis formed as a cylinder, this system moreover necessitates expensive safety provisions in the area where the user moves in order to prevent damage to the object to be transported and also to the operating staff.
The stroke of the pneumatic linear axis 31 depends on the room height and the size of the cryostat. Local adjustment of the linear axis length 31 cannot be economically performed owing to complex seals, the tools that are required etc., for which reason any re-mounting necessitates complex work preparations and customer-specific material procurement.
The transport device disclosed in [2] is self-supporting (not shown in FIG. 2) and highly massive. Due to the resulting net weight, it must not be fixedly connected to the cryostat 1 (danger of tilting). Due to the fact that this transport device is not fixedly connected to the vibration-damped cryostat 1 and has no active vibration damping itself, one tried to manage with the flexible hose 33 between point D′ and point Z (FIG. 2b). This hose 33, however, cannot damp all vibrations and is constricted when the cryostat 1 is lowered (this is the case when cryostats 1 are being filled with helium or nitrogen). The diameter of the hose 33 is reduced by the constriction, which causes repeated jamming of the object to be transported.
[1] describes a pneumatically operating transport device consisting of a tube (inclined tube 14″) that is disposed at an inclination and extends from point B″ to point C″ (FIG. 2a), and in which the NMR measuring sample located in a sample holder can be transported by means of pressure gas in an upward or downward direction (FIG. 1). An input point A″ is located at a location that can be easily accessed by the user and point C″ is located close to the upper opening of the room temperature tube (RT tube) that belongs to the NMR cryostat 1.
The transport device of [1] is disadvantageous in that the object to be transported and thereby the highly sensitive samples contained therein are rotated out of the vertical axis due to the position of the inclined tube 14″. Friction is generated between the inner tube surface and the sample holder due to the inclined position of the tube 14″ and the net weight force of the object to be transported. Depending on the angle position of the inclined tube 14″ and the position of center of gravity of the object to be transported (which changes in dependence on the sample fill level, diameter of the NMR sample tube and sample holder type), the object to be transported tends to get jammed between the inner surface of the inclined tube 14″ in various ways. These jamming effects are particularly severe in the transition areas between the upper and lower pivot tube and the inclined tube 14″, and further increase the more the inclined position of the inclined tube 14″ approaches the horizontal position. Moreover, the required room height becomes larger the closer the operating staff wishes the easily accessible location to be with respect to the cryostat 1 and the larger the diameter of the cryostat 1. FIG. 2a shows how these requirements result in that the path between point C″ and the supply point Z becomes larger and larger and thereby also the required room height. When the inclined tube 14″ terminates in the table top of a console and is fixedly connected thereto (see document [1], FIG. 2, element 65, description paragraph 35), mechanical vibrations can be transferred from the table top of a console to the transport device and from there to the cryostat 1, which is to be prevented.
It is therefore the underlying purpose of the invention to propose an inexpensive transport device for transporting an object to be transported to the upper end of an RT tube of a cryomagnet system, which is compact and at the same time also ensures reliable transport of samples.